Apertured nonwoven webs are used in various industrial and consumer products sectors. For example, apertured nonwoven webs are used to produce disposable sheets, disposable garments, filtration masks and hygiene and sanitary products, such as sanitary napkins, incontinence pads and baby diapers.
Apertured nonwovens can be manufactured using various techniques. One technique entails obtaining a thermobonded or spunbonded nonwoven and aperturing the nonwoven using a set of raised needles as described in U.S. Pat. Nos. 4,128,679 and 4,886,632.
Apertured nonwovens intended for use as absorbent article topsheets that exhibit one way, valve-like behaviour can be created by laminating a plastic sheet of film prepared using traditional extrusion techniques (for example, a thin sheet of LDPE delivered through a cast or blown extrusion head) and aperturing the film and nonwoven combination using solid forming techniques known in the art (e.g., calender perforation of laminates as described in U.S. Pat. No. 4,780,352). Laminates generated by joining or aligning a formed film and a nonwoven can be perforated by mechanical techniques as described in U.S. Pat. No. 7,204,907.
Another technique for creating apertured webs, particularly fiber based apertured webs, uses thermomechanical contact perforation such as pin perforation or an engraved cylinder that is in contact with a smooth cylinder, as described in U.S. Pat. Nos. 5,814,389, 4,128,679 and 4,886,632. Yet another technique for creating a web uses a vacuum apertured laminate as described in U.S. Pat. No. 4,995,930.
Current apertured webs used in absorbent articles as the skin contacting cover layer such as a topsheet, are limited in their ability to be skin soft, discrete (quiet), moldable to the skin, and/or absorbent of fluid to maintain a dry feeling and convey the sensation of dryness. Laminates of film and nonwoven as described above, especially in U.S. Pat. No. 4,995,930, uses nonwoven fiber as the skin facing material to deliver softness benefits. However when such laminates are wet, the fiber cover retains the fluid and the film material has no ability to drain the fibrous nonwoven matrix. The user's body may develop a skin rash as a result of the adjacent topsheet moisture. Such a laminate may also be noisy when the wearer is walking because it lacks flexibility to mold to the body since it cannot be prepared with a low basis weight (e.g., less that 27 gsm). In addition, such a laminate is expensive since it requires purchasing and combining a plastic film with the nonwoven material. As a consequence, the laminate and/or product made using the laminate may be stiff, noisy, and scratchy or provide a generally unpleasant or wetness sensation.